Power converters, such as flyback converters and other switch-mode power supplies, are common in modern power supplies and are utilized in both alternating current (“AC”) to direct current (“DC”) conversion, and DC-to-DC conversion with galvanic isolation between the input and outputs of the power supply. In general, a flyback converter is a power converter having a magnetic element that is split to form a transformer which provides the galvanic isolation. In general, a flyback converter has a primary-side and secondary-side. The primary-side of the flyback converter includes a primary-side switch (such as, for example, a transistor), and the secondary-side includes another switch (such as, for example, a diode) to rectify the current produced by the secondary-side of the flyback converter. In operation, flyback converters generally operate in a switched-mode that periodically turns on and off the primary-side switch that supplies current to the magnetic element.
Peak-current limiting is implemented in flyback converters to ensure that a current through the magnetic element is controlled below a saturation limit of the magnetic element. Additionally, peak-current limiting is implemented in flyback converters to ensure that a maximum sustained power of the flyback converter is maintained at a level that is equal to or less than a power level that the flyback converter can sustain in terms of temperature, voltage, and/or current stress. However, as an input voltage (i.e., a bulk voltage) of the flyback converter varies, a given current through the magnetic element will produce a respective varying power. Thus, primary-side current limiting sometimes includes provisions to compensate for such input voltage variation to achieve constant power limiting of the flyback converter.